The present invention relates to an ultrasonic transducer driving circuit and an ultrasonic diagnostic apparatus and, more particularly, relates to an ultrasonic transducer driving circuit and an ultrasonic diagnostic apparatus that make it possible to quickly return, from a positive voltage or negative voltage to a ground voltage, the voltage of an output line which outputs the positive voltage or the negative voltage or the ground voltage to an ultrasonic transducer, and that allow for a reduction in circuit size.
Heretofore, there is known an ultrasonic diagnostic apparatus including a positive FET (Field Effect Transistor) which outputs a positive voltage onto an output line to an ultrasonic transducer at on state, a negative FET which outputs a negative voltage onto the output line to the ultrasonic transducer at on state, and a driver circuit which turns the positive FET and the negative FET on/off (e.g., see Patent Document 1 and Patent Document 2). [Patent Document 1] Japanese Unexamined Patent Publication No. 2006-101997 (FIG. 10, FIG. 12, FIG. 14)
[Patent Document 2] Japanese Unexamined Patent Publication No. 2004-358133 (FIG. 2)
The above ultrasonic diagnostic apparatus of prior art has a problem in which, when a pulse of a positive voltage or negative voltage is applied to the output line, the voltage on the output line does not quickly return from the positive voltage or negative voltage to the ground voltage because of capacitance of the output line.
To address this, it is conceivable to incorporate an active ground clamp circuit that forcibly returns the output line to the ground voltage. However, a FET with a capacity of 1 A or more is needed in the active ground clamp circuit and this poses a problem that the circuit size becomes larger.